Picrotoxin is an antagonist of GABA receptors.
Ehrenberger K. et al : Suppressive action of picrotoxin, a GABA antagonist, on labyrinthine spontaneous nystagmus and vertigo in man. (http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=7064710&dopt=Abstract)
